Hybrid electrostatic-impact printer

ABSTRACT

Hybrid electrostatic-impact printer combining a retractable web feeder, on which is mounted an electrostatic printer, and a mechanical impact printer. The hybrid printer allows for rapid receipt and transmission of alpha-numeric information with easy adaptation from the electrostatic mode to the mechanical impact mode by movement of the web feed roller into and out of engagement with the mechanical impact printer.

United States Patent [191 Rice, Jr.

[ HYBRID ELECTROSTATIC-IMPACT PRINTER [75] lnt'entor: Philip J. Rice, Jr., Atherton, Calif.

[73] Assignee: American Express Investment Management Corporation, San Francisco, Calif.

[22] Filed: Mar. 6, 1972 [21] Appl. No.: 231,957

[52] U.S. Cl. 178/25, IOI/DIG. 13, 346/74 ES [51] Int. Cl. H04l 17/00 [58] Field of Search 178/42, 38-40,

178/34-36, 33 B, 33 R, 28, 27, 25, 23; 346/74'JES; IOI/DIG. 13

[5 6] References Cited UNITED STATES PATENTS 3,686,678 8/1972 Robbins et al. 346/74 ES [4 Dec. 25, 1973 Primary Examiner-Thomas W. Brown Attorney-Stephen S. Townsend et al.

[57] ABSTRACT Hybrid electrostatic-impact printer combining a retractable web feeder, on which is mounted an electrostatic printer, and a mechanical impact printer. The hybrid printer allows for rapid receipt and transmission of alpha-numeric information with easy adaptation from the electrostatic mode to the mechanical impact mode by movement of the web feed roller into and out of engagement with the mechanical impact printer.

8 Claims, 3 Drawing Figures HYBRID ELECTROSTATIC-IMPACT PRINTER BACKGROUND OF THE INVENTION 1. Field of the Invention In a communications terminal at which an operator interacts with a computer, the most common printing device used today is a mechanical printer (teletypewriter) with a keyboard and a print wheel. Because of its construction, the printer is limited to a printing speed of about ten characters per second. The communications line (voice grade phone line) can carry up to 200 characters per second.

By using electrostatic printing, which is capable of receiving and printing characters at a rate of greater than 200 characters per second, the communications line can be efficiently utilized. However, when the electrostatic printer is beingused to send messages, such high speeds are not normally required, since transmission is carried out by a human operator. Furthermore, the electrostatic printer has the severe failing, that there is a substantial time lag between depositing the charge patterns and the visibility of the printed character. In electrostatic printing, the character is first deposited as a charge pattern on a dielectric-coated web and is subsequently made visible by being exposed to an electrostatic toner. Until the toner is applied, the characters are not visible. Therefore, the operator cannot see what is being sent until several lines have been printed. Any corrections must occur after a substantial portion of the suceeding message has already been transmitted. This is an evident drawback in using an electrostatic printer for transmitting messages.

It is therefore desirable to have an apparatus which would efficiently utilize the capacity of the communication line, while allowing for effective transmission, which is limited to the speed of the operator. Preferably,-relatively minor modification of existing transmission equipment would be required, while greatly enhancing the efficiency of the receiving mode.

2. Description of the Prior Art Electrostatic developers are described in U. S. Pat. No. 3,461,843 and print heads in copending application Ser. No. 109,072, filed June 16, i971, now US. Pat. No. 3,718,936, issued Mar. 1, 1973. Combinations of typewriters with other means are found in U. S. Pat. Nos. 660,149, 1,224,121 and 2,686,469.

SUMMARY OF THE INVENTION In a communications terminal for receiving and sending alpha-numeric information, a combination of an electrostatic printer and impact printer is employed. A substantially stationary impact printer is provided with a web feed. roller mounted for translational motion, whereby the roller can move out of engagement with the-teletypewriter mechanism with simultaneous positioning of the electrostatic printer into its operating position, as well as the reverse movement. Thus, rapid receipt of printed messages is achieved, while permitting efficient utilization of the message sending apparatus,

with the operator being aware of the message being transmitted or received substantially simultaneously with its transmission or receipt.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 2 is a diagrammatic view of the hybrid printer in the receiving mode;

FIG. 3 is a side view of the electrostatic printer and feed roller without the rack and guide.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS A method and apparatus are provided for substantially simultaneous printout of received and transmitted information. A conventional impact printer is modified to accommodate an electrostatic printer. By these means, in a communications center, where messages can be received at high speed from a computer, the electrostatic printer allows for high speed printing of the information which is received. When transmitting meassages, the operator is able to see the message being transmitted prior to or simultaneously with its transmission.

A conventional teletypewriter can be employed, or any other mechanism for receiving and transmitting alpha-numeric information which does not require translational movement of the feed roller. The major modification of the teletypewriter is replacement of the conventional feed roller with a roller which is adapted for electrostatic printing. The electrostatic printer is mounted on the roller so as to be able to be moved from a first non-operating position to a second operating position.

Mechanical means moves the feed roller out of engagement with the Teletype mechanism and the electrostatic printer mechanism into its operative position and then returns the roller to engagement with the Teletype mechanism and moves the electrostatic printer to a non-operative position. Rotational movement of the web feeder means is controlled by whichever mode is operative.

The web feeding means has a capstan and pinch roller. The pinch roller is fixedly mounted on a shaft or two pins extending outwardly from the sides of the pinch roller. The electrostatic printer is mounted on a yoke or arms, the arms being on opposite sides of the pinch roller and rotably mounted on the shaft or pins of the roller. Means are providedfor moving the roller into and out of juxtaposition to the impact printer of the Teletype mechanism, while simultaneously moving the electrostatic print head from a position out of the way of the Teletype mechanism into a position where the alpha-numeric information can be readily seen as it emerges past the print head.

The pinch roller is frictionally engaged with a capstan or driving roller to provide for positive movement of the web or paper. The capstan is actuated in accordance with the needs of the electrostatic printer or the Teletype mechanism as required. Alternatively, by employing a clutch mechanism, the pinch roller can engage the normal advance mechanism, used in a Teletype, e.g., ratchet and pawl, and be driven by the capstan, when the electrostatic printer is in operation.

For further understanding of the subject invention, the accompanying figures will be considered. A hybrid printer 10 has as its major elements a Teletype mechanism 12, an electrostatic printer 14, a continuous web or paper feeding mechanism 16, and means for translationally moving the paper feeding mechanism 18.

In FIG. 1, the invention is shown in the transmitting or sending mode, where the Teletype is operative. A normal Teletype is used, having as its major elements a font drum 22, a ribbon spool 24, a hammer 26 and means forcontrolling the various elements of the Teletype mechanism 25, which are not specifically shown. Also not shown is the mechanism for transmitting signals in conjunction with the printing of a message.

. The Teletype mechanism has a paper guide 28, which is in juxtaposition to the pinch roller 32, when the Teletype mechanism is in operation. The pinch roller 32 is mounted on shaft 34. The shaft 34 is journalled in pinion gear 36, which is in operative engagement with rack 38. A roller track guide 42 is provided on each side of the pinch roller 32, with the shaft 34 extending into the track 44. While only complementary track guides 42 may be employed on opposite sides of the pinch roller 32 to maintain the roller 32 aligned, it may be desirable to have complementary pinions and racks on both sides of the roller 32 to insure alignment and to provide sufficient mechanical force for rotating the print head 46 without jamming of the gear teeth.

In the sending mode, the print head 46 is positioned out of the way of the Teletype mechanism 12. If the roller was divided into four quadrants by horizontal and vertical axes, the print head would be in the lower left quadrant. The print head is not in operation in this mode.

A driving roller or capstan 48 is operated by a motor 52 through mechanical connections which are indicated by the dotted line 54. A paper roll 56 is mounted on pin 58. The roll may be appropriately tensioned so as to take up any slack, which results from translational movement of the pinch roller 32. Paper 62 is fed from the paper roller 56 downwardly extending under the print head 46, past the paper guide 28 and between the pinch roller 32 and the capstan 48. The paper will be dielectric paper which can be used both with the impact printer and the electrostatic printer.

When the Teletype mechanism is being employed, the movement of the capstan 48 will be controlled by the Teletype mechanism 25. The capstan 48 will move the paper one line, as each line is completed by the t'eletypewriter operator, in accordance with normal typing practice. Means not shown may be employed for taking up the paper 62, as it is fed from the capstan 48 or passing the paper 62 over the paper roll 56, so as not to become entangled with any of the mechanism.

When the operator has finished transmitting a message, and a message is to be received, the paper or web feeding mechanism is moved out of juxtaposition with the Teletype; mechanism 12. A rotary solenoid 64 has a cable 66 which passes over cable wheel 68 and is rotably connected, for example, by means of a pin and hearing, at point 72 to shaft 34. The cable 66 is fixedly attached to dowel 74 in rotary solenoid 64.

In order to move the print head into the operating position, the receiving mode for the hybrid printer 10, the rotary solenoid 64 is actuated. The rotary solenoid 64 turns in a counterclockwise direction, pulling on the.

cable 66 which in turn pulls on the shaft 34. The pinion gear 36 rides freely on the shaft 34 and is fixedly connected to the arm 76 to which the print head 46 is mounted. The pinch roller 32 moves upwards and rearwards, at an acute angle to the horizontal.

As the pinion gear 36 rides on the rack 38, the pinion gear turns slowly moving the print head 46 into its operating position as depicted in FIG. 2. The print head 46 has an electrostatic image transducer 78 with a plurality of wires 82 for operating the electrostatic forming means.

Digital data are applied to a decoder which can conveniently be a read-only memory. Decoded signals are fed to 35 high voltage drivers and thence to the print head 46 by means of leads 82. At the same time, the desired print position is selected by applying a high voltage pulse to the appropriate conducting ring 90 in the pinch roller 32 by means of lead 92 via the sliding contact 88.

The pinch roller 32 is in effect an insulated drum having a plurality of conducting rings, one for each image which can be printed by the print head. These conducting rings are charged in coordination with the print head at the positions where an image is to be printed. Since sliding contacts are employed, the leads extend out from one side of the pinch roller to a fixed post which is connected to the voltage source. The particular means for connection may be carried out according to various means known in the art.

The paper is advanced via the web feeding mechanism 16 in response to a paper advance" signal derived from the decoded data, which is fed to the motor 52.

A thorough description of the developing system may be found in U. S. Pat. No. 3,461,843. Therefore,'o nly a brief description will be provided'here. In order to develop the image, a reservoir, not shown, is connected through an inlet tube to inlet 84 on one side of the applicator to carry liquid toner thereto. The applicator 80 is connected back to the reservoir by means of an outlet tube connecting outlet 86 to the reservoir to enable constant circulation of liquid toner between the applicator and the reservoir. A circulating pump is used to maintain the circulation.

The applicator has a divider plate 96 dividing the applicator into an inlet chamber 98 and an outlet chamber 102. Developing liquid, generally in the form of a liquid toner comprising particles suspended in a carrier liquid enters the applicator 80 through inlet 84 and fills the inlet chamber'98. Most of the liquid passes around the lower edge 104 of the dividing plate 96 and then flows out of the applicator 80 through outlet 86. Some of the liquid toner contacts the paper at the slot 106 to develop the electrostatic image on the paper 62.

After the paper 62 has left the ,print head 46, the paper engages the capstan 48 and is squeezed between the capstan 48 and pinch roller 32. The squeezing action of the capstan 48 and pinch roller 32 serves to additionally squeeze the toner on the paper 62. Since toner frequently accumulates on the side of the capstan 48 opposite the print head, a vacuum cleaner 94 is employed to remove excess toner.

The paper 62 then continues on and may be collected on a roll or passed over a bar and then allowed toaccumulate on the floor. In this way, the paper 62 does not interfere with the continuous operation of the hybrid printer.

When the completed message has been received, and the operator wishes to return the hybrid printer to the sending mode, the rotary solenoid 64 is then deenergized. Since the roller track guide 42 is at an angle to the normal plane of the desk or floor, gravity may be sufficient to provide for the return of the roller 32 to its original position. However, to enhance the rate of return of the roller 32 to its original position and assure the proper seating of the shaft 34 in the track 44, springs, a cable to the rotary solenoid 64 in the opposite direction of the cable 66 or other conventional means may be used. I

As the roller is lowered along the track 44 in the direction of the Teletype mechanism 12, the turning of the pinion gear 36, as it moves along the rack 38, moves the print head 46 downward and backward so as to move the print head 46 out of the way of the Teletype mechanism 12. By use of clutches, the paper being printed can be made to travel at the same time as the electrostatic print head 46 during mode shifting, if desirable.

During manual action-sending mode, all voltages are removed from the pinch roller and from the print head so as not to mark the paper. The toner bath may remain on without causing undue staining or wetting of the paper.

The hybrid printer is now ready to be used according to the sending mode. The cycle of transferring from the receiving to the sending mode may be repeated as often as required and can be rapidly carried out in a simple and efficient manner. The hybrid printer provides for efficient use of a communications terminal in accommodating the high speed information transmission from a computer. At the same time, the inefficiency in employing an electrostatic printer when transmitting messages is avoided. That is, the hiatus between the time the message is typed and the time the message becomes visible, so the operator can see it, is made vanishingly small.

The subject apparatus also provided for utilization of available Teletype equipment with relatively minor modification. The mechanism is based on modifying the roller to accommodate itself to both electrostatic printing and impact printing, while keeping a major portion of the Teletype mechanism substantially intact. The electrostatic printer readily moves into and out of position for operation and out of the way of the Teletype mechanism, when the Teletype mechanism is being employed. Continuous web or paper feeding is achieved from the same source with both modes of employment of the hybrid printer.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the invention, as limited only by the scope of the appended claims.

What is claimed is:

1. A hybrid printer for use at a communications terminal wherein alpha-numeric information in printed form is substantially simultaneously observable with the transmission or receipt of electrical signals relating to said alpha-numeric information, comprising:

teletypewriter means for simultaneously printing alpha-numeric information by mechanical impact and transmitting electrical signals associated with said alpha-numeric information; web advance means comprising a capstan in operative engagement with a pinch roller; electrostatic printing means rotatably connected to said web advance means; and means for moving said web advance means from a first position with said web advance means in operating engagement with said teletypewriter means 6 and with said electrostatic printing means in a nonoperating mode to a second position with said web advance means removed from operating engagement with said teletypewriter means and with said electrostatic printing means in an operating mode.

2. A printer according to claim 1, wherein said moving means moves said web advance means rearwardly and upwardly from said teletypewriter means.

3. A printer according to claim 1, comprising in addition track guides positioned on opposite sides of said pinch roller and wherein said pinch roller has pins extending axially outwardly from the sides of said pinch roller and engaging said track guides and said moving means has a cable attached to one of said pins for moving said web advance means along said track guide.

4. A printer according to claim 1, wherein said pinch roller has a shaft extending outwardly beyond both sides of said pinch roller and said electrostatic printing means comprises a print head having first and second arms rotably mounted on said shaft, one arm on each side of said pinch roller.

5. A printer according to claim 4, wherein said moving means comprises a pinion gear fixedly connected to one of said arms, and a rack in operative engagement with said pinion gear.

6. A hybrid printer for use at a communications terminal for receiving and transmitting messages electronically and imprinting the messages received and transmitted, which comprises: teletypewriter means for simultaneously printing alpha-numeric information and transmitting electrical signals associated with said alpha-numeric information, having mechanical impact means moving horizontally during printing; web advance means comprising a pinch roller and a capstan, wherein said capstan is positioned above the horizontal plane through the axis of said pinch roller, said pinch roller having first and second pins extending axially outwardly beyond each of the sides of said pinch roller; electrostatic printing means having a print head with image forming and developing means in juxtaposition to said pinch roller, and first and second arms extending from opposite sides of said print head and rotatably mounted on said pins; means for moving said web advance means from a first position in operative engagement with said Teletype means to a second position removed from said Teletype means, while moving said electrostatic printing means from .a non-operating mode to an operating mode, comprising first and second guide tracks on opposite sides of said pinch roller engaging said first and second pins, means for moving said pins along said guide tracks, a pinion gear affixed to said first arm and rotatably coaxially mounted on one of said pins, and a rack in gear tooth engagement with said pinion gear; and means for controlling the movement of said web advance means in operative connection with said Teletype means and said electrostatic printing means.

7. A printer according to claim 6, wherein said means for moving said web advance includes a solenoid drum connected to one end of a cable with the other end of said cable connected to one of said pins.

8. A hybrid printer for use at a communications terminal wherein alpha-numeric information in printed form is substantially simultaneously observable with the transmission or receipt of electrical signals relating to said alpha-numeric information, comprising:

teletypewriter means for simultaneously printing alpha-numeric information by mechanical impact and transmitting electrical signals associated with said alpha-numeric information;

with said electrostatic printing means in a nonoperating mode to a second position with said web advance means removed from operative engagement with said teletypewriter mechanism and with said electrostatic printing means in an operating mode. 

1. A hybrid printer for use at a communications terminal wherein alpha-numeric information in printed form is substantially simultaneously observable with the transmission or receipt of electrical signals relating to said alpha-numeric information, comprising: teletypewriter means for simultaneously printing alpha-numeric information by mechanical impact and transmitting electrical signals associated with said alpha-numeric information; web advance means comprising a capstan in operative engagement with a pinch roller; electrostatic printing means rotatably connected to said web advance means; and means for moving said web advance means from a first position with said web advance means in operating engagement with said teletypewriter means and with said electrostatic printing means in a non-operating mode to a second position with said web advance means removed from operating engagement with said teletypewriter means and with said electrostatic printing means in an operating mode.
 2. A printer according to claim 1, wherein said moving means moves said web advance means rearwardly and upwardly from said teletypewriter means.
 3. A printer according to claim 1, comprising in addition track guides positioned on opposite sides of said pinch roller and wherein said pinch roller has pins extending axially outwardly from the sides of said pinch roller and engaging said track guides and said moving means has a cable attached to one of said pins for moving said web advance means along said track guide.
 4. A printer according to claim 1, wherein said pinch roller has a shaft extending outwardly beyond both sides of said pinch roller and said electrostatic printing means comprises a print head having first and second arms rotably mounted on said shaft, one arm on each side of said pinch roller.
 5. A printer according to claim 4, wherein said moving means comprises a pinion gear fixedly connected to one of said arms, and a rack in operative engagement with said pinion gear.
 6. A hybrid printer for use at a communications terminal for receiving and transmitting messages electronically and imprinting the messages received and transmitted, which comprises: teletypewriter means for simultaneously printing alpha-numeric information and transmitting electrical signals associated with said alpha-numeric information, having mechanical impact means moving horizontally during printing; web advance means comprising a pinch roller and a capstan, wherein said capstan is positioned above the horizontal plane through the axis of said pinch roller, said pinch roller having first and second pins extending axially outwardly beyond each of the sides of said pinch roller; electrostatic printing means having a print head with image forming and developing means in juxtaposition to said pinch roller, and first and second arms extending from opposite sides of said print head and rotatably mounted on said pins; means for moving said web advance means from a first position in operative engagement with said Teletype means to a second position removed from said Teletype means, while moving said electrostatic printing means from a non-operating mode to an operatIng mode, comprising first and second guide tracks on opposite sides of said pinch roller engaging said first and second pins, means for moving said pins along said guide tracks, a pinion gear affixed to said first arm and rotatably coaxially mounted on one of said pins, and a rack in gear tooth engagement with said pinion gear; and means for controlling the movement of said web advance means in operative connection with said Teletype means and said electrostatic printing means.
 7. A printer according to claim 6, wherein said means for moving said web advance includes a solenoid drum connected to one end of a cable with the other end of said cable connected to one of said pins.
 8. A hybrid printer for use at a communications terminal wherein alpha-numeric information in printed form is substantially simultaneously observable with the transmission or receipt of electrical signals relating to said alpha-numeric information, comprising: teletypewriter means for simultaneously printing alpha-numeric information by mechanical impact and transmitting electrical signals associated with sald alpha-numeric information; web advance means for moving a web in synchrony with the printing of said alpha-numeric information; electrostatic printing means in juxtaposition to said web advance means; and means for moving said web advance means in a first position with said web advance means in operating engagement with said teletypewriter means and with said electrostatic printing means in a non-operating mode to a second position with said web advance means removed from operative engagement with said teletypewriter mechanism and with said electrostatic printing means in an operating mode. 